WHY IS OIL COMING FROM MY VALVE COVER WHERE IT RUNS TO THE FRESH AIR DUCT?

1995 Mitsubishi Eclipse • 475 miles

I just built the motor and turboed the engine, done 300mile brake in then had it tuned to 16psi boost. While tuning everything was fine and went well, afterwards I noticed under boost it was spitting oil out of the valve cover line that is supposed to hook to my "fresh air duct" when I noticed this I did a compression teste and all 4cylenders read 150psi which I think is correct since I put weisco 8-8-1 pistons in it, I also installed eagle h-beam rods, chromoly rings, supertech valves and springs with titanium retainers, plus cleivite bearings, along with arp head and main studs and a walboro 255 lph fuel pump with apexi neo ecu. So I dont see why I would b having any problems. Plz help me understand why this is occurring with the oil issue, thanks : )

A wet compression test is when you add a small quantity of oil to the cylinder and re test compressions, the oil will temporally seal the ring land and if comps come up you have compression blow by past the rings, normally you want to see a max of 10% variation only.